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| TDA7296S |
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 STMICROELECTRONICS
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5 page 
APPLICATION SUGGESTIONS (see Test and Application Circuits of the Fig. 1) The recommended values of the external components are those shown on the application circuit of Fig- ure 1. Different values can be used; the following table can help the designer. COMPONENTS SUGGESTED VALUE PURPOSE LARGER THAN SUGGESTED SMALLER THAN SUGGESTED R1 (*) 22k INPUT RESISTANCE INCREASE INPUT IMPEDANCE DECREASE INPUT IMPEDANCE R2 680 Ω CLOSED LOOP GAIN SET TO 30dB (**) DECREASE OF GAIN INCREASE OF GAIN R3 (*) 22k INCREASE OF GAIN DECREASE OF GAIN R4 22k ST-BY TIME CONSTANT LARGER ST-BY ON/OFF TIME SMALLER ST-BY ON/OFF TIME; POP NOISE R5 10k MUTE TIME CONSTANT LARGER MUTE ON/OFF TIME SMALLER MUTE ON/OFF TIME C1 0.47 µF INPUT DC DECOUPLING HIGHER LOW FREQUENCY CUTOFF C2 22 µF FEEDBACK DC DECOUPLING HIGHER LOW FREQUENCY CUTOFF C3 10 µF MUTE TIME CONSTANT LARGER MUTE ON/OFF TIME SMALLER MUTE ON/OFF TIME C4 10 µF ST-BY TIME CONSTANT LARGER ST-BY ON/OFF TIME SMALLER ST-BY ON/OFF TIME; POP NOISE C5 22 µFXN (***) BOOTSTR APPING SIGNAL DEGRADATION AT LOW FREQUENCY C6, C8 1000 µF SUPPLY VOLTAGE BYPASS C7, C9 0.1 µF SUPPLY VOLTAGE BYPASS DANGER OF OSCILLATION (*) R1 = R3 for pop optimization (**) Closed Loop Gain has to be ≥ 26dB (***) Multiply this value for the number of modular part connected MASTER UNDEFINED SLAVE -V S +3V -VS +1V -VS D98AU821 Slave function: pin 4 (Ref to pin 8 -VS) Note: If in the application, the speakers are connected via long wires, it is a good rule to add between the output and GND, a Boucherot Cell, in order to avoid dangerous spurious oscillations when the speakers terminal are shorted. The suggested Boucherot Resistor is 3.9 Ω/2W and the capacitor is 1 µF. TDA7296S 5/11 |
